Referring to FIG. 1, a conventional exercise machine 1 is illustrated, which includes two handlebars 11 and two press buttons 12. Each press button 12 is mounted on a top end of a respective one of the handlebars 11, and serves to adjust parameters of the exercise machine 1, such as resistance, speed, and so on.
As such, a user generally presses the press buttons 12 with his/her thumbs to adjust the parameters of the exercise machine 1. However, with such structural design, it may be difficult for the user to maintain a firm grip on the handlebars 11 during the button-pressing process, which does not follow the principles of ergonomics. Moreover, the press buttons 12 are generally dome-type switches made of silicone rubber, which are prone to eventually fracture or lose electrical contact with their inner circuit boards (not shown). Furthermore, if any part of the press button 12 malfunctions, the entire press button 12, along with its inner circuit board, may need to be replaced, which is fairly inconvenient.